Receiver for signaling.



No. 727,328. Y PATENTED MAY 5, 1903..

' R. A. FBSSENDEN.

RECEIVER FOR SIGNALING.

APPLICATION FILED DEG. 29, 1902.

FIELI- IE 1 "DEE l4 1 [ml] gVgTNESSES: QIISVENTOR I AWL- limits dramasPatented May 5, 1903.

PATENT FFICE.

RECEIVER FOR SIGNALING.

SPECIFICATIQN forming part of Letters Patent No. 727,328, dated May 5,1903. Application filed December 29, 1902. Serial No. 136.967. (Nomodel.)

To (tZZ whout it may concern:

Be it known that I, REGINALD A. FEssEN- DEN, a citizen of the UnitedStates, residing at Fort Monroe, in the county of Elizabeth City andState of Virginia, have invented or discovered certain new and usefulImprovements in Receivers for Signaling, of which improvements thefollowing is a specification.

The invention described herein relates to certain improvements inreceivers for signaling. It -is characteristic of most forms ofimperfect coutact-reoeiverse. g., coherers now in usethat theyare formedofsmallirregular particles of conducting material, so that when broughtinto contact with each other a surface of one particle may be in contactwith a point of another particle, but when decohered and again, broughtinto contact with each other a surface of one may bear upon a surface ofthe other. By reason of this variation in the areas of contact thecurrent passing through the coherer will vary, rendering the signalsreceived uncertain. Ooherers have also been used in which the contactingsurfaces are uniform; but the same surfaces are always brought intocontact again after decoherence. Where the same non-conducting film isconstantly acted on by the current, its character is so changed as tocause variations in the voltage required to actuate-the coherer.

The object of the present invention is to insure uniformity andreliability of action of receivers of the imperfect contact type and toinsure their freedom from the effects of electrical or mechanicaldisturbances.

In the accompanying drawings, forming a part of this specification,Figure 1 is a diagrammatic view illustrative of my improved receivingapparatus, and Fig. 2 illustrates a modified form of the apparatus.

In the practice of my invention I employ an imperfect contact-receiverof the self-restoring typesuch, for example, as that shown anddescribed-consisting of the parts or members 1 and 2, so constructedthat one shall have movement relative to the other, so that thecontacting surfaces can be changed with sufficient frequency to giveoperative uniformity. Convenientformsfortheseparts consist of a disk anda second member stationary relative to the direction of movement of thedisk. The disk is mounted upon a spindle 3, which may be rotated by anyconvenient means, such as the clockwork 4E. This disk may be formed ofcarbon or carbonized structured material, such as carbonized velvet, ormetal, such as an alloy of gold and bismuth, the latter forming five percent. of the alloy, or aluminium or mercury or osmium or iron. The otherpart or member 2 of the coherer may be formed of carbon or metal. Bothparts or members may be formed of similar material. When the part ormemher 1 is formed of carbon, the part or member 2 is made by preferencein the form of a roller mounted so as to bear upon the face of the diskand to be rotated by contact therewith, as shown in Fig. 2. When usingthis construction, the disk is preferably constantly rotated by anysuitable mechanism. As an indicating mechanism a telephone 13 in thelocal circuit may be used.

It is characteristic of my improvement that new surfaces are c onstantly broughtinto C9111.

wa mth EH1 ptherTtlibhlitactew-i. e., area'ana shape of ni'snrracesnrcontact being uniform and similar, so that for each coherence the actionis practically the same and that any insensitive position of the contactdoes not persist on account of the fact that new surfaces are constantlypresented. As on account of irregularities in the motion or vibration orsurfaces the contacts will never be entirely uniform, and hence in thecase, for example, of the rolling contact shown in Fig. 1 irregularnoises will be produced in the telephone 13 which will interfere withthe signaling, the indicating apparatus is designed so as to respondonly to impulses having a frequency equal to the number of electricaldischarges per second at the sendingstation-'. e, if at thesending-station there are one'hundred sparks per second the indicatingapparatus should respond only to im' pulses of that frequency. This isobtained by tuning the receiving apparatus either electrically, as byputting in the capacity 15 and the inductance 16 in circuit with thetelephone 13, as shown in Fig. 2, or mechanically, when the inductancesand capacity'may be omitted and a telephone having instead of adiaphragm a tongue in tune to the desired frequency, as shown in Fig. 2,where 18 is a single telephone-magnet, and 19 a metallic tongue adaptedto vibrate at the desired frequency.

I am aware that imperfect contact devices have been constructed whereone or more of the contacts have been made movable for purposes ofadjustment; but the motion herein described does not refer to motion ofadjustment which effects a change of sensitiveness by changing thepressure, but of motion for, maintaining the sensitiveness practicallywithout changing and for renewing the surfaces of contact.

The invention is not limited as regards the terms of the broad claims toany specific form or construction of self -restoring imperfectcontact-receivers.

I claim herein as my invention- 1. An imperfect contact-receiver forsignaling, having in combination two parts or members each having auniform surface,

means for moving one of said surfaces relative to the other, and anindicating mechanism adapted to respond only to impulses of apredetermined frequency,substantially as set forth.

2. An imperfect contact-receiver for signaling, having in combinationtwo parts or members each having a uniform surface, means for moving oneof said surfaces relative to the other independent of the action of theelectromagnetic waves, and an indicating mechanism adapted to respondonly to impulses of a predetermined frequency, substantially as setforth.

In testimony whereof I have hereunto set my hand.

REGINALD A. FESSENDEN.

Witnesses:

JNO. W. BAILY, '1. L. SCLATER.

